Powering through: Chris Froome has established a 51 second lead with team-mate Richie Porte in second.

Jeff Pachoud, AFP

Chris Froome used the first tough mountain stage to take command of the Tour de France, leaving two-time champion Alberto Contador and Cadel Evans in his wake on a gruelling climb in the Pyrenees to seize the leader's yellow jersey.

Froome entered the Tour as the favourite after finishing second last year behind countryman and Sky teammate Bradley Wiggins, who is not defending his title because of an injury.

And after Froome's performance on Saturday, the race looks like it is his to lose.

"I must be among the happiest men in the world today," Froome said after the eighth stage finish at the ski resort of Ax 3 Domaines.

"There are two weeks left but we want to keep the yellow jersey."

Froome leads Contador by nearly two minutes, with former champions Andy Schleck and Cadel Evans much further back, ahead of another tough mountain stage on Sunday.

"More than anything today we've got a bit of a psychological advantage over the others," Froome said.

"We've worked for months to be in this position."

Stretching his overall lead

In the overall standings, Froome is 51 seconds ahead of Australian teammate Richie Porte and leads third-place Alejandro Valverde by 1:25.

Meanwhile, Contador is 1:51 behind in seventh spot; Schleck is 4:00 back in 21st and Evans is 4:36 adrift in 23rd.

This is the 100th edition of the Tour - and the first since Lance Armstrong was stripped of his seven straight titles (1999-2005) for doping.

Froome's ride on Saturday resembled Armstrong at his best, when the American used to punish his opponents early in the race to take control.

Froome was asked after the stage to vouch that he is riding clean.

"One hundred per cent," he responded. "It's normal that people ask questions in cycling.

"I certainly know the results I'm getting, they're not going to be stripped ... I think the sport (has) changed. If you look at it logically the sport is in a better place now than it has been."

Still early days

The 28-year-old attacked early into the day's second big climb and only Porte, who finished the stage 51 seconds behind in second, was anywhere near him.

Contador grimly held on as long as he could and was dropped by Froome long after 2010 champion Schleck and the 2011 champion Evans had already been left behind.

"I tried to find my rhythm because it was a bit too fast for me," Schleck said. "It's only the first day of the mountains and it's not over yet."

Froome took the yellow jersey from South African cyclist Daryl Impey, his former training partner, who crawled over the line 7:50 behind in 35th spot.

His GreenEdge teammate and former leader Simon Gerrans was almost half an hour behind, the Australian outfit reigned to losing the yellow jersey after four days in flat country.